Patent literature: JP-A-2012-55786
Harber-Bosch process is known as an industrial synthesis method of ammonia. However, since a fossil fuel is used as a raw material in the Harber-Bosch process, a depletion of resources may not be averted. Since a reaction at high temperature and pressure is required in the Harber-Bosch process, a large amount of energy may be consumed. Thus, a development of a method alternative to the Harber-Bosch process may be required.
For example, patent literature 1 discloses a nitrogen fixation material that includes a nanoparticle of titanium oxide having a photocatalytic function and a conductive polymer covering the nanoparticle of titanium oxide. The nitrogen fixation material fixes nitrogen in the atmosphere as ammonium salt or the like when light is irradiated to the nitrogen fixation material in the presence of nitrogen and moisture such as the atmosphere and it is possible to recover the nitrogen. That is, it is possible to produce ammonia using the nitrogen and moisture contained in the atmosphere as a raw material in place of the fossil fuel and using natural energy such as sunlight as energy.
The applicants of the present disclosure have found the following with respect to conventional nitrogen fixation materials. The conventional nitrogen fixation material may solve a problem of a raw material and energy. However, a generation speed of the ammonia may be low. That is, according to the conventional nitrogen fixation material, a generation amount of the ammonia may not sufficiently increase after a light irradiation.